New purchase of a 3124KB questions

I'm looking to purchase a 2012 3124 KB. I've read many posts on the board re vents, batteries, fans, wheels ... If those of you that are experienced with the line were to purchase new, what would be on your hit list beyound what shows on the options page. Your help would be much appreciated.

Also, what is a fair discount from the dealer retail price? (20% or what)